Just in case this is of interest to anyone else, I will update. We changed the oil filter, which looked pretty heavily clogged with junk, but looks can be deceiving. There were also some small aluminum chips.

After changing the filter a restart produced no change in oil pressure measurement. Zero.

So, we opened the filter housing and found it full of oil. Then we took the oil pressure sender off and started the car. The first time there was nothing, maybe a slight spray. We tried it again and oil flowed profusely, making a substantial mess. Then I sucked on the end of the sender fitting and got a little oil out (yeah, in my mouth but it is Delvac 1, so I am expecting it to do wonders on the inside). Did the start and stop thing without the sender in place a few times and got the same result, a gush of oil. So we put the pressure signal sending unit back in, and started. Got 2.5 Bar, and then watched it slowly drop to 1.5 Bar. Started again, and it went to 1.5 Bar and kind of stayed there. The engine sounds perfectly normal through all this, but there is no slinging of oil around on the camshafts at the front of the engine under the oil fill cap.

Confounded. Did a few searches and found a few others with this same problem, or sort of, but never got to the resolution part. Any ideas guys? Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)